1. Field of the Invention
The present invention relates to chairs.
2. Description of the Prior Art
Chairs having a single vertical leg are known. Such chairs have a support plate supporting a seat portion in which the seat portion is hinged thereto in the vicinity of the back rest. The back rest is coupled to the support plate by means of a piston and cylinder assembly to enable the angle of inclination of the back rest to be varied.
The disadvantage of such a chair is that any change in the angle of inclination of the back rest is accompanied by a similar change in the angle of inclination of the seat portion. Thus for example when the back rest is pivoted forwardly towards the occupant, the rear edge of the seat portion drops and accordingly the front edge of the seat portion is effectively lifted to cause the legs of the occupant of the chair to be lifted off the floor, which can be unpleasant.
To counter the effect produced by the pivotal displacement of the back rest, a mechanical spring, for example a leaf spring, whereof the rigidity is set once and for all at the production works, is installed on the support. The leaf spring results in a relatively large structural height of the support in which it must be housed.
It is an object of the invention to provide an improved chair. A further object of the invention is to provide a chair in which the ratio between the inclination of the back rest and the inclination of the seat portion can be readily adjusted and the need for a mechanical leaf spring is obviated.